Lighting fixtures, e.g. the recessed "can lights" used in architectural lighting, have traditionally used a variety of techniques to efficiently direct or otherwise manipulate their light output. For example, the fixtures may be designed to be recessed into a wall or ceiling, may incorporate reflectors or lenses or may incorporate baffles or shields.
However, manipulation of the light output or increase efficiency often comes at the price of a less pleasing appearance when the lighting fixture is turned off or on. Recessed "can lights" for example, look like holes in the ceiling plane when they are off; "wall washer" fixtures, i.e. fixtures set into a ceiling and configured to throw light onto an adjacent wall, often project below the surface of the ceiling and are often of low efficiency; reflectors used to direct light downwards can create glare to a viewer's eye.
The problem of unattractive lighting fixtures has become worse with the advent of high-efficiency, compact fluorescent bulbs replacing simple incandescent bulbs in many lighting fixtures. These compact fluorescent bulbs, with their large, twisted glass tubes,. are unpleasing to the eyes, and since they are much less of a point source than incandescent bulbs, do not lend themselves to simple, efficient reflector design.
At present, the practical solutions to the above problems are limited. For example, certain grids of vanes have been placed in front of the light source to shield a viewer's eyes from glare coming from the bulb or its reflector or to make a light look like less of a hole in the ceiling. Sophisticated and precisely shaped reflectors can be incorporated into a compact fluorescent lamp's fixture to try to direct light from the bulb efficiently in the desired pattern. PAR-type lamps can be mounted at an angle inside a recessed fixture to wash a wall with light without a bulb or fixture hanging below the plane of the ceiling.
Those approaches each suffer from significant disadvantages. Current grids of shielding vanes can reduce the efficiency or restrict the angle of illumination of a fixture. Sophisticated and precisely shaped reflectors are expensive to manufacture. PAR-type lamps are substantially more expensive than standard-type bulbs.
Accordingly, it would be highly desirable to have other techniques to manage the light output from a lighting fixture as well as provide an aesthetically pleasing appearance when the fixture is in the either on or off state.